


Chasing Tail

by random_writer



Category: Ao no Exorcist | Blue Exorcist
Genre: Hand Jobs, Incest, M/M, Masturbation, Smut, Tail Sex, Tails
Language: English
Status: Completed
Published: 2018-04-07
Updated: 2018-04-07
Packaged: 2019-04-19 16:12:07
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,636
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/14241024
Author URL: https://archiveofourown.org/users/random_writer/pseuds/random_writer
Summary: Rin learns a little about Demon Anatomy - with the help of his brother.





	Chasing Tail

**Author's Note:**

> Disclaimer: I don't own these characters, but I am going to Hell...

“Rin, are you listening?” Yukio growled as he studied his brothers slumped shoulders and sleepy eyes. When he didn’t receive a response, the demon pulled a handgun from the holster at the base of his spine and shot the ceiling. His patience had come to its end. 

Everyone in the classroom jumped in their seats. Rin jolted as if he had been struck by lightning, his bright blue eyes overly wide to compensate for the fact that he had nearly fallen asleep during the lesson. The sudden movement startled Kuro, who was curled on the front corner of his desk. The demon cat arched its back and growled before stalking from the classroom in search of a more peaceful place to nap. Rin eyeballed the cat enviously.

The classroom was silent; the students too startled, or too afraid, of what their newly turned demon instructor would do. Yukio ignored their frightened stares which clung to his twitching tail. He was beginning to hate the unruly appendage. It seemed to have a mind of its own, always dancing behind his back like a teasing child.

Ever since his demon heritage had come to the surface, people at the cram school had given him a wide berth. They were afraid, and who could blame them? He had almost been responsible for the rise of Satan Himself.

He bit the inside of his cheek. Guilt consumed his every waking moment. It took most of his daily energy reserves to summon the courage to get out of bed, and Rin’s slapstick attitude wasn’t helping.

“Rin, have you heard a single thing I’ve said?” Yukio asked his twin brother. He holstered his weapon and placed his hands firmly against Rin’s wooden desk. It was a stance designed to intimidate, but it didn’t have the desired impact on his inconsiderate sibling.

“I heard you ask if I was listening.” Rin smirked. His pointed canines left slight dimples on his bottom lip. Yukio’s eyes clung to the smooth skin. His fingers dug into the cool wooden table.

Since his transformation, Yukio was less capable of suppressing the strange combination of desire and rage which he felt towards his brother. It left him feeling equal parts needy and guilty. It was his curse; a curse he would suffer alone and in silence. 

“Anything else?”

“Something about a hippopotamus.”

In a moment of blind rage, Yukio gripped the front of his brother’s shirt and pulled. Rin fell forwards, his palms flat against the table as he awkwardly tried to right himself. He was half-standing, half-leaning against the desk. His teeth were bared as if he were just as eager for a fight.

“Hippocamp.” Yukio growled into his brother’s face. “The horse-fish hybrid demon.”

Rin’s anger was quickly replaced with understanding.

“Ah, that makes more sense.”

Yukio was beginning to wonder why he bothered. The younger twin sighed, his head bowed with defeat as he released his brother’s tie. Rin flopped back into his chair as if nothing had happened.

“See me after class.” Yukio turned to make his way back to the front of the class. He should have known better.

The moment his back was turned, a warm hand wrapped around his tail. Yukio froze. His entire body went stiff as a familiar, and unwelcome sensation overwhelmed him.

A demon’s tail was highly sensitive, as Rin knew from experience. His tail had been pulled during a fight with Amimon months earlier. He had described it to Yukio as one of the single most painful experiences of his life. Not unlike being kicked in the balls… ten times in a row… by a kangaroo.

However, in this moment, pain was not what Yukio felt.

He had never felt such potent pleasure. He clenched his fists and bit the inside of his cheek. Still, a moan threatened to rip from his chest. The smooth skin of Rin’s palm sent pleasurable shocks up his spine. He tried to pull away, but the friction almost sent him to his knees.

“What’s the matter, teach?” Rin teased, his fist tightening ever so slightly. Yukio’s head span as the blood in his head rushed southward. _Did Rin realise what he was doing? They were in public._

“Rin, let my tail go.” Yukio said. The gravelly sound of his own voice made him blush. He wanted to move, to keep walking and let his tail glide through Rin’s fingers, but he didn’t trust himself to do so without moaning. Or begging for more. He wouldn’t humiliate himself in front of his class.

Rin snickered. “What, can’t handle a little pain?”

The class began to murmur with varying levels of awkwardness. Yukio’s embarrassment reached new heights as he realised that THEY understood. THEY knew exactly what he was feeling. At least some of them were paying attention in class, he thought ironically.

“Rin, let him go.” Shiemi whispered, her face a shade of pink that rivalled Yukio’s.

Confused by the thick tension in the room, Rin released Yukio’s tail, crossed his arms over his chest and leaned back in his chair.

Yukio released a sigh of relief. His body thrummed with aftershocks, his tail twitching nervously as if unsure of what happened next. Pulling together the last of his dignity, he squared his shoulders and turned to face the class. The glare he sent Rin from behind his spectacles could have killed a lesser demon.

“Can anyone tell me what a Hippocamp’s weakness is?” Yukio said, his voice level once more. Nobody spoke. Dozens of eyes were staring at him, intent for the first time in weeks.

“Anyone?!”

Eight hands immediately rose to answer his question.

***

Rin was confused. Yukio refused to make eye contact with him for the remainder of the lesson. All he had done was play a harmless prank, right? Pulling Yurkio’s tail couldn’t have hurt that badly.

The hushed whispers from his classmates were making him uncomfortable. Even Shiemi couldn’t look at him without blushing. Hell, Yukio was the one who was supposed to have been humiliated, so why did he feel like he had done something wrong? An unpleasant feeling began to coil in his belly.

Class ended without the usual fanfare. Rin felt the need to apologise, though for what he had no clue. He approached Yukio’s desk, but before he had a chance to speak his sibling gathered his things and bolted.

“Yuri!” Before Rin could take chase, his path was blocked by his classmates.

“You pervert.” said Suguro.

“What?” The unpleasant coil tightened in Rin’s belly.

“Do you have any idea what you did?”

Rin shrugged. “A prank. It hurts to have your tail pulled.”

Shiemi shook her head, her blush deepening. Surprise crossed Suguro’s face.

“I take it back. You aren’t a pervert, you’re an idiot.” Suguro slapped the back of Rin’s head before quitting the room.

“Read a book, dumbass.” Izumo added. She threw a bound textbook onto his desk before following the rest of Rin’s friends from the classroom. They didn’t wait for him. Hurt and confused, Rin eyeballed the book Izumo had left him. On the cover in gold cursive was: **_Demons Anatomy_**.

He sighed and began flicking through the book. Yukio had told him to read this book more times than he could count. Perhaps he should have listened.

He was aimlessly scanning the page on demon tails when the word **_PLEASURABLE_** seemed to jump off the page. He backtracked and began reading the beginning of the paragraph. The more he read, the deeper his blush became until, finally, he slammed the book closed and placed his head in his hands.

“Well, shit.” He cried as he realised he had just grabbed his brothers demonic dick in front of the entire classroom.

***

Yukio dumped the lecture notes on his table and removed his coat before rolling into bed, fully clothed. He tried not to think of what he would say to Rin when they next met. He couldn’t recall ever wanting to punch his twin brother more. It had been over an hour, and he was still hot from the feeling of Rin’s fingers gripping his tail.

 _You are sick,_ he thought to himself. It was so wrong that the thought of his brother’s hands on his tail, gently stroking and pulling, turned him on.

The memory alone raised Yukio’s temperature, and he began angrily pulling off layers of clothing until he was left in nothing but his black boxer shorts. He squirmed and rolled around, gasping every time his oversensitive tail brushed against the sheets. Uncomfortable, and aware of only one solution to his predicament, Yukio reached behind him and loosely fisted his tail.

A gasp ripped past his lips before he could stifle it with logic. The furry appendage flicked lazily back and forth, encouraging him to explore further. Carefully, he ran his fingers along the length of his tail and towards its end. Pleasure sent him flopping back into the pillows. His rapidly growing erection tented the front of his boxer shorts.

He had never done this before. Sure, he was more than familiar with the pleasures of his human body, but was yet to fully explore the potential sensation of his demonic side.

He was just about to run his fingers through the thick fur at the tip of his tail when Rin barged through the closed door. In his hand was a hardcover textbook with gold writing on the cover. Yukio recognised it as one of the readings recommended for his class; Demons Anatomy. Someone must have given Rin a copy, because he knew for a fact that Rin would never have purchased it.

“Yukio, I’m so sorry about…” Rin’s eyes widened as they took in his brothers dishevelled state. His glasses were crooked, and his usually pristine hair was wild. Rin’s eyes darted to Yukio’s obvious arousal. “Ah, that.”

Yukio ground his teeth. He didn’t have the strength of will to remove his hands from his tail, but he did manage to keep them still while he growled at his brother. It wasn’t like they hadn’t caught each other in similar states before, but it had been many years.

“Apology excepted. Now, go away!”

To Yukio’s dismay, Rin froze. He stood in the doorway, his shoulder blades shifting invitingly beneath his shirt.

“What are you waiting for? Get out!” Yukio’s voice was deep with desire. He swallowed a moan when his tail moved involuntarily in his palm. Clearly, it was growing impatient. Yukio could relate. He didn’t know how much longer he could hold himself in check before he would break. _Damn, if only Rin would hurry up and leave!_

Rin nodded when he made his decision. He stepped back into the room and closed the door. The sound of the lock engaging echoed in Yukio’s ears. Without hesitation, Rin crossed the room and sat on the edge of Yukio’s bed.

“What are you… Rin!” Yukio’s back arched as Rin’s warm hands wrapped around his tail… again. They felt a thousand times better than his own.

“This feels good?” Rin furrowed his brow, intrigued by his brother’s reaction. He would never have thought stroking the appendage would warrant such an intense response.  

“Ah… Ah...” Yukio’s chest heaved. He moved his hands until his fingers dug into the flesh of his thighs. At least there they wouldn’t be tempted to pull Rin closer.

“Do you want me to stop?” Rin’s voice was steady.

Their eyes met, both feeling exposed. Yukio knew he should say yes, but he didn’t have enough sense to push Rin away. His higher brain function was suffering under the intense desire. He whimpered when Rin released his tail. _Was he leaving?_

“Wait, Rin…”

Rin pulled himself onto the bed and propped his back against the wall. Then he dragged Yukio up so that he was wedged between his thighs; his back against Rin’s chest. Yukio’s tail was pressed between them. Rin’s hands were gentle as they trailed between his shoulder blades and down his back until they reached the base of his spine.

“Just so you know, I want this just as much as you.” Rin’s voice was barely a whisper, his breath ghosting over the tip of his ear.

“Please…” Yukio felt like he was falling apart. This desire had been building up for years. If Rin didn’t put his hands to good use shortly, he would surely explode.

“Patience, brother.” Yukio could hear the smirk in Rin’s voice. Desperate and frustrated, Yukio took the only revenge he could in his position. He shifted, pressing his weight back against Rin.

He was stunned, and encouraged, when he felt Rin’s clothed erection press into his back. He rocked his hips more purposefully, and smirked at Rin’s hiss of desire.

Not to be outdone, Rin immediately got to work on his brother’s tail. Yukio’s eyes rolled into the back of his head when Rin’s hands finally began to move along its length. Lust pooled in his belly and made his back arch. Unable to bear the ache, Yukio reached into his boxer shorts and fisted his own erection.

“So impatient.” Rin teased as his fingers dragged lightly through the thick fur at the tip of his tail. Throaty moans burst from his throat, the erotic sounds slipping past his lips no matter how he tried to stifle them. The dual stimulation of his hand on his dick and his brothers on his tail was quickly becoming too much. Rin recognised this, and pulled Yukio’s hands away from his erection before he made himself come. He held Yukio’s palms face-down against his thighs, which bracketed Yukio’s hips. Yukio’s fingers immediately dug into the coarse denim.

“Leave them there.” Rin said.

Yukio whined. “No, I need…”

“What about what I need?” Yukio shivered as Rin moved one hand from his tail and ran his fingers delicately along the curve of his neck. Moments later, his fingers were replaced with his lips as he began sucking at the sensitive skin. Yukio’s hips rocked, desperate for friction.

Meanwhile, Rin’s free hand travelled slowly down Yukio’s chest, pausing to roll each nipple between his thumb and forefinger before continuing downwards. His fingers passed lightly over his erection, and Yukio almost came undone. He gasped as Rin’s gentle pressure increased.

Rin suddenly had a vice-like grip on Yukio’s hip and used the leverage of the wall to pull his hips back while simultaneously rocking his own forwards. The motion effectively ground Rin’s erection against the base of Yukio’s spine, brushing against the most sensitive region of his tail.

“Mmmmm.” Rin sighed against Yuriko’s throat, grateful to finally have some relief. He built up a rhythm, both men now chasing their desire with selfish abandon. Soon, Rin’s hands abandoned Yukio’s tail for more self-seeking endeavours. He grabbed his brothers hips and began thrusting forwards.

“Ah… Yuki...”

With Rin distracted, Yukio took the opportunity to grasp his aching cock and matched the rhythm of his brother’s grinding. The wave of his orgasm tore a surprised cry from his throat. The sound was enough to push Rin over the edge, both climaxing within moments of each other.

Rin collapsed against the wall, holding Yukio upright with his arms loosely draped around his waist. Both were gasping for breath as they tried to process their new set of circumstances.

“What now?” Rin asked, his voice betraying his fear.

Yukio was silent, his mind whirring. Finally, he released a long breath and turned to stare at his brother.

“I’m going to shower.” He said tersely. Rin’s eyes were wide and pleading. He needed confirmation that this hadn’t been a horrible mistake.

“Why don’t you join me? There are a few things in that book on demon biology which I think you might find enlightening.”

Rin couldn’t supress his smile. “I’d like that.”

**Author's Note:**

> Thanks so much for reading! Any feedback is welcome, and kudos make me smile. :D


End file.
